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Mesa Boogie Fuse

Discussion in 'Amps and Cabs [BG]' started by skinnypete, Aug 13, 2007.

  1. skinnypete


    Oct 7, 2004
    New York, NY
    I have a Bass 400+ and the fuse blew.

    The fuse is rated at 6.25 amps 250 volts slo-blo.

    I went looking for those specs and the closest I could find was a 6. The guy at the electronics store said that as long as I don't go over 6.25 I should be okay and that 6 should work.

    Does anyone have any knowledge about fuses in a Boogie, will a 6 amp fuse work and is it recommended for extended use? I checked the manual and there is no info.

  2. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Seems like that should be fine. It's close. You definately don't want one rated higher than what's recommended.
  3. anderbass


    Dec 20, 2005
    Phoenix. Az.
    My 400+ has (factory) fuse labeling info that calls for a 8 amp slo-blo fuse.
    (small sticker right next to the fuse / yours could have fallen off)
    Unless your amp has different fuse specs printed on it, I'd assume yours calls for the same fuse too.
    (an undersized fuses can blow, in a perfectly good amp)

    My 400+ was blowing its (8-amp) fuse when I bought it. On mine the problem was being caused by one of the (inner row) power tubes that had rattled loose, and was not fully seated into its socket.
    I retentioned its (very-loose) retaining clamp, fully inserted the power-tube and never had another problem.

    Here's some older threads on this subject:
  4. kobass

    kobass Supporting Member

    Nov 3, 2003
    Outside Boston
    I used to own a Mesa M-Pulse 600. I never had any problems with fuses, but I always like to have some spares in my gig bag just in case. I had a hard time finding fuses that Mesa had spec'd. I ended up calling Mesa and they sent me a bunch of them in the mail-no charge!
  5. tadawson


    Aug 24, 2005
    Lewisville, TX
    The schematics I got from Mesa for the 400plus show an 8 amp fuse for 120 volts, and a 4 amp for 240 volt . . . . straight from the horses mouth. Apparently the 6.25 was something that someone stuck in there in a pinch. Make sure that the voltage rating on the fuse is good for 120 volts or better too - there are auto fuses that are only rated for 32 volts or so, which won't protect the amp properly, since they can arc over at higher voltages.

    - Tim
  6. Caca de Kick

    Caca de Kick Supporting Member

    Nov 18, 2002
    Seattle / Tacoma
    The Bass 400 uses a 6.25A slo-blo, while the Bass 400+ is an 8.0A slo-blo. You may want to call Mesa with your serial number and verify, it could be possible but doubtful, probably labelled wrong if it's an early 400+.
    Yes you can use a slightly under rated fuse but not over rated.

    If your amp is blowing fuses it's because there's a tube going bad. Find the bad tube and remove it, or you'll keep popping fuses. You can keep playing it with one missing til you replace the tube.

    I have an old 400, and 6.25 slo-blo's are very hard to find. So when I ran across a commercial marine shop that had 6.25's, I bought all they had. If you truly need a 6.25 I can send you one.
    agedhorse likes this.
  7. skinnypete


    Oct 7, 2004
    New York, NY
    Thanks everyone. And thanks for the offer of a 6.25 fuse. I bought a 6 and they are working fine.
  8. tadawson


    Aug 24, 2005
    Lewisville, TX
    If you truly have a 400+, and not a 400, it should have been an 8 (as per the Mesa schematics) . . . the 6.25 was only for the 400 . . . so, if you really push it, expect it to let go again . . .

    - Tim
  9. Justin Warren

    Justin Warren

    Mar 1, 2018
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Please call customer service today or on Monday and talk with the service dept. They will be able to give you the correct advice for your unit. What is silk screened on the back of your amp by the fuse holder? I don't know enough about the revision history of your amp to be able to give you accurate advice. My docs. show 8A slow blow (for 120V) but I don't know which transformer you have and there might have been a revision, which is why I hesitate to recommend without one of the guys who specialize in the legacy product history weighing in.

    (the factory is closed Fridays)

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